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Perfect reconstruction image modulation based on BEMD and quaternionic analytic signals

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science china({2. sciences) 2011年第12期54卷 2622-2634页

作者： QIAO LiHong 1 , NIU KaiFu 2., WANG Ning 2.& PENG LiZhong 2.1 College of {3. science and {2., Henan University of Technology, Zhengzhou 450001, china 2.School of Mathematical sciences, Peking University, Beijing 100871, china 1. College of information science and {2. Henan University of Technology Zhengzhou 450001 China2. School of Mathematical Sciences Peking University Beijing 100871 China

Image modulation represents image by meaningful characters such as image instantaneous amplitude and instantaneous frequency. A perfect reconstruction image modulation method is proposed. In detail, the bidimensional empirical mode decomposition (BEMD) is first improved to adaptively decompose image into monocomponents. Then by the quaternionic analytic method, suitable analytic signals is acquired. A new polar form is further proposed to modulate images, then seven characters are derived including instantaneous amplitude and instantaneous frequencies. We demonstrate the techniques on both synthetic and natural images, depict the needle program of the estimated frequencies and obtain the reconstructions that are the same with the original images. The applications in image segmentation and separation establish the validity of characterizing images of this type as sums of locally narrow band modulated components.

关键词： perfect reconstruction image modulation AM-FM representation BEMD quaternionic analytic signals

Influence of Pr Content on the Sructure and Giant Magnetoresistance of Pr_x(Co_(40)Ag_(60))_(100-x) Granular Films

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Journal of Wuhan University of Technology(Materials science) 2011年第1期26卷 1-3页

作者：成钢 School of Materials science and {2. Guilin University of Electronic Technology Guangxi Key Laboratory of information Materials

Prx（Co40Ag60）100-x （x=0, 0.5, 1, 1.5, 2. 3. granular films have been prepared by DC magneto controlled sputtering method. The XRD data indicated that Pr element favors the （111） plane preferential orientation. Magnetic measurements indicate that the average size of magnetic particles decreases as Pr content increases. For relatively low addition of Pr to CoAg granular films, Pr element can enhance GMR value and a peak value of about -14.3. is obtained at x=1.

关键词： giant magnetoresistance granular films magnetic particle

Simulation study of phase retrieval for hard X-ray in-line phase contrast imaging

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science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 450-458页

作者： YU Bin1,2. PENG Xiang1,2. TIAN Jindong1, NIU Hanben1, DIAO Luhong3.& LI Hua3.1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Institute of Optoelec- tronics, Shenzhen University, Shenzhen 518060, china 2. State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 3.0072.china 3. Key Laboratory of Intelligent {2. Processing, Institute of Computing Technology, Chinese Academy of sciences, Beijing 100080,china 1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education Institute of Optoelectronics Shenzhen University 518060 Shenzhen China 2. State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University 300072 Tianjin China 3. Key Laboratory of Intelligent information Processing Institute of Computing Technology Chinese Academy of Sciences 100080 Beijing China

Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.

关键词： X-ray optics, phase contrast imaging, phase retrieval, angular spectrum, hard X-ray.

PDMS prism-glass optical coupling for surface plasmon resonance sensors based on MEMS technology

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science china({2. sciences) 2010年第10期53卷 2144-2158页

作者： GENG ZhaoXin 1,2., LI Qing 3., WANG Wei 1 & LI ZhiHong 1 1 Institute of Microelectronics, Peking University, Beijing 100871, china 2.S{3. of {2. engineering, Minzu University of china, Beijing 100081, china 3.S{3. of sciences, Changchun University of science and Technology, Changchun 13.000, china 1. Institute of Microelectronics Peking University Beijing 100871 China2. School of Information engineering Minzu University of China Beijing 100081 China3. School of Sciences Changchun University of Science and Technology Changchun 130000 China

A miniaturized surface plasmon resonance (SPR) chip has been developed for biomedical and chem-ical analysis with low cost and high performance. The techniques of bulk silicon micromachining and polymer replication were used to fabricate the Kretschmann SPR sensor composed of a Polydimethylsiloxane (PDMS) prism, a coupling glass and microchannels. The plasmon properties of thin metal films were investigated theoret-ically based on Fresnel analysis, with optical boundary conditions pertaining to the surface plasmon resonance at the gold/water and gold/air interfaces. The theoretical results show that difference in the refractive index (RI) between the PDMS prism and the coupling glass layer affect the precision of the SPR angle and the SPR curve. Meanwhile, the period of the interference fringe attaching on the SPR curve increases with an increase in wavelength and a decrease in the refractive index of the coupling glass layer. The gold thickness of 50 nm is required while employing a fixed incident wavelength of 650 nm, to achieve optimum SPR excitation conditions and the sensor sensitivity. The characteristics of this SPR sensor were evaluated in the angular interrogation mode of employing the incident wavelength of 650 nm in air and water media, respectively. The obtained SPR angles were approximately consistent with the theoretical ones.

关键词： surface plasmon resolance polymer microfluidic PDMS

Building a next generation Internet with source address validation architecture

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science in china(Series F) 2008年第11期51卷 1681-1691页

作者： WU JianPing1,3.REN Gang1,3.& LI Xing2.3.1 Department of Computer science,Tsinghua University,Beijing 100084,china 2.Department of Electronic {2.,Tsinghua University,Beijing 100084,china 3.Tsinghua National Laboratory for information science and Technology(TNList) ,Beijing 100084,china Department of Computer science Tsinghua University Beijing 100084 China Department of Electronic engineering Tsinghua University Beijing 100084 China Tsinghua National Laboratory for information science and Technology (TNList) Beijing 100084 China

The IP packet forwarding of current Internet is mainly destination based. In the forwarding process, the source IP address is not checked in most *** causes serious security, management and accounting problems. Based on the drastically increased IPv6 address space, a ＂source address validation architecture＂（SAVA） is proposed in this paper, which can guarantee that every packet received and forwarded holds an authenticated source IP address. The design goals of the architecture are lightweight, loose coupling, ＂multi-fence support＂ and incremental deployment. This paper discusses the design and implementation for the architecture, including inter-AS, intra-AS and local subnet. The performance and scalability of SAVA are described. This architecture is deployed into the CNGI-CERNET2.infrastructure a large-scale native IPv6 backbone network of the china Next Generation Internet project. We believe that the SAVA will help the transition to a new, more secure and dependable Internet.

关键词： IP source address validation network architecture network security

Second-order consensus in networks of dynamic agents with communication time-delays

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Journal of Systems engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2. Huajing Fang3. and Hua Wang4 1. School of Navigation, Wuhan University of Technology, Wuhan 43.063. P. R. china 2. Wuhan Second Ship Design and Research Institute, Wuhan 43.064, P. R. china 3. Department of Control science and engineering, Huazhong University of science and Technology, Wuhan 43.074, P. R. china 4. Department of Aerospace and Mechanical engineering, Boston University, Boston MA02.15, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China Wuhan Second Ship Design and Research Institute Wuhan 430064 E R. China Department of Control science and engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and Mechanical engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

Minimal systems of generators for central division algebra and semi-simple algebra

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Chinese science Bulletin 1998年第21期43卷 1777-1780页

作者： QIU Qizhang 1 and SUN Ling 2.1. Department of Mathematics, Wuhan University, Wuhan 43.072. china 2. Department of information {2., Wuhan University, Wuhan 43.072. china. Department of Mathematics Wuhan University Wuhan China Department of information science Wuhan University Wuhan China

Suppose that F is a field of characteristic zero and (ⅰ) D is a finite-dimensional central division algabra over F; (ⅱ) A is a finite-dimensional semi-simple algabra over F. It is proved that as F-algebras, D and A ... 详细信息

关键词： central division algebra semi-simple algebra generator minimal system of generators.

Quantum secret sharing between multiparty and multiparty with four states

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science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 572-580页

作者： YAN FengLi1, GAO Ting2.& LI YouCheng1 1 College of Physics and information engineering, Hebei Normal University, Shijiazhuang 050016, {2. 2.College of Mathematics and information science, Hebei Normal University, Shijiazhuang 050016, {2. 1. College of Physics and information engineering Hebei Normal University Shijiazhuang 050016 China 2. College of Mathematics and information science Hebei Normal University Shijiazhuang 050016 China

A protocol of quantum secret sharing between multiparty and multiparty with four states was presented. It was shown that this protocol can nullify the Trojan horse attack with a multi-photon signal, the fake-signal attack with Einstein-Podolsky- Rosen pairs, the attack with single photons, and the attack with invisible photons. In addition, the upper bounds of the average success probabilities were given for dishonest agent eavesdropping encryption using the fake-signal attack with any two-particle entangled states.

关键词： quantum secret sharing, security, Einstein-Podolsky-Rosen pairs

Characterization of plastic flow in two Zr-based bulk metallic glasses

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science china(Technological sciences) 2006年第4期49卷 414-424页

作者： XING Dongmei1,2. ZHANG Taihua1, LI Weihuo3.& WEI Bingchen3.1. State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sci- ences, Beijing 100080, china 2. College of Physics and Electronic {3. {2., Tianjin Normal University, Tianjin 3.0074, china 3. National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of {2.s, Beijing 100080, china 1. State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China 2. College of Physics and Electronic information science Tianjin Normal University Tianjin 300074 China 3. National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Plastic deformation behaviors of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, microindentation and uniaxial compression. The Be-containing BMG exhibits a signifi- cantly improved overall plastic strain compared with the Be-free alloy during compressive tests. Both BMGs show a loading-rate-dependent serrated flow during nanoindentation measurements, but the Be-containing alloy exhibits a much lower critical loading rate for the disappearance of the serration than the Be-free BMG. The shear band patterns de- veloped during plastic deformation are investigated by microindentation technique, wherein much higher shear band density is found in the Be-containing alloy than in the Be-free alloy, indicating an easier nucleation of shear bands in the former BMG. The dif- ference in the plastic deformation behavior of the two BMGs can be explained by a free volume model.

关键词： Bulk metallic glass, plastic deformation, shear band, nanoindentation.